The name of this famed hospital was once a byword for the horrors of medical and psychiatric care.

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

One of only two commuter aerial tramways in the United States.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

A crumbling hospital from the 1850s on Roosevelt Island.

During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.

Remnants of a Victorian garden feature sitting in public woodland.

The most unique castle in all of Southern California, entirely constructed from repurposed materials.

A modern English garden of eccentric beasts, follies, and oddities.

Living trees form the structure of an open-air palace.

This small town in the Netherlands has no roads but instead, miles of canals and over 100 bridges.

A small but immensely extravagant palace built by the "Night King."

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.

A cluttered and astounding collection of antiquities and curiosities.

Terrifying derelict military hospital once housed a recuperating Hitler.

Ruins of a 10th century church tucked away deep in a botanical garden.

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.

Iceland's "Smoky Valley" is a beautiful river that is shrouded in a constant cover of steam clouds.

Australian Lake set aglow by Noctiluca Scintillans.

Abandoned medieval hill town.

A 300-yard long natural tunnel runs through a ridge deep in the Appalachian Mountains.

This dramatic sea spire is home to the world's rarest insect and is part of the lost continent of Zealandia.

Quite simply the largest tree in the world (by volume).